The specific synaptosomal uptake of 3H 2-deoxy-D-glucose (3H 2-DG) was progressively reduced in cerebral ischemia of 30-180 minutes duration. Two major groups were observed in which: (1) the specific entry of 3H 2-DG was decreased 25-53% (relative uptake 77-47%), and (2) the reduction from 45-72% (relative uptake 55-28%) as compared to the relative uptake of control (100%). After 180 minutes of ischemia, the specific uptake of 3H 2-DG was almost completely lost. The decreased synaptosomal transport function could not be restored by addition of various metabolites to the incubated media. However, complete recovery of synaptosomal 3H 2-DG uptake was observed 60 minutes after reestablishment of cerebral circulation in all gerbils subjected to 60 and 180 minutes of ischemia.